A METHOD FOR REDUCING THE CONCENTRATION OF NITROGEN OXIDE IN A GAS REMOVAL PLANT TO GET NITRIC ACID TO GET NITCH ACID DURING A SHUT-OFF AND / OR INSTALLATION STARTING AND SETTING TO GET NITRIC ACID TO BE SWITCHED AND TO ORGANIZE A NITROGEN ACID TO SET A NITROGEN ACID

摘要

The method of reducing the concentration of nitric oxide in the exhaust gas in a plant for the production of nitric acid, which is operated under pressure and which is equipped with a residual gas purification system during shutdown and / or start-up of the installation, and the residual gas purification system is designed to remove nitrogen oxides from the exhaust gas for steady state operation. Method, characterized in that during start-up and / or during shutdown of the plant for the production of nitric acid, pressurized off-gas containing nitrogen oxides from the plant for the production of nitric acid and the gaseous reducing agent for nitrogen oxides are passed through a reactor filled with catalyst in addition to the residual gas purification reactor, the content of NO in the exhaust gas is reduced by catalytic reduction, or the content of NO in the exhaust gas is reduced by means of catalytic reduction, and the content of NO in the exhaust gas is reduced by catalytic reduction and / or by catalytic decomposition in an additional reactor. In addition, the described installation for producing nitric acid for the implementation of this method. When applying the method or when using the installation, it is possible to perform colorless start-up and shutdown of installations for the production of nitric acid without problems, and the content of nitrogen oxides in the exhaust gas during start-up and / or shutdown can be significantly reduced.